I'm going to try and be quick with my thoughts here:
I don't find the Primal Weathers to be problematic and rather find that their presence makes the metagame a lot more interesting. Desolate Land and Primordial Sea are great checks to one another and Delta Stream certainly exists for like Corviknight. Defensively these abilities offer a whole new avenue to the game as you can run Desolate Land Heatran and give yourself a Water immunity + extra Fire damage. There's actually a dynamic between stuff like DLand and normal Water immunities: the former stop protecting you if your weather gets canceled out by PSea/Stream, while the latter doesn't but instead finds itself vulnerable to Teravolt/Turboblaze. It adds a ton to creativity when designing a team.
The biggest issue with Primal Weather IMO is when you pair it with weather abusers like Venusaur and Barraskewda. Personally I've not had much trouble fighting them but I have no qualms with them getting axed. I think clausing out Primal Weather + Speed Boosting Ability is the way to go.
This is all my opinion but having dedicated Weather teams sounds really annoying to build against since there are 4 different styles and multiple potential abusers to cover for. If we get rid of Primal Weathers I imagine we'd end up in a metagame dominated by Weather teams, which would likely result in them facing bans as well. Primal Weathers offer a check to these teams that require Weather builds to make some sacrifices in order to succeed - sacrifices that can make them easier to handle as a whole without immediately making them unviable. Just because I added something like Primordial Sea Ferrothorn to my team doesn't mean a prospective Sun team can't add something that threatens or lures Ferrothorn in so it can be removed.
I don't find the Primal Weathers to be problematic and rather find that their presence makes the metagame a lot more interesting. Desolate Land and Primordial Sea are great checks to one another and Delta Stream certainly exists for like Corviknight. Defensively these abilities offer a whole new avenue to the game as you can run Desolate Land Heatran and give yourself a Water immunity + extra Fire damage. There's actually a dynamic between stuff like DLand and normal Water immunities: the former stop protecting you if your weather gets canceled out by PSea/Stream, while the latter doesn't but instead finds itself vulnerable to Teravolt/Turboblaze. It adds a ton to creativity when designing a team.
The biggest issue with Primal Weather IMO is when you pair it with weather abusers like Venusaur and Barraskewda. Personally I've not had much trouble fighting them but I have no qualms with them getting axed. I think clausing out Primal Weather + Speed Boosting Ability is the way to go.
This is all my opinion but having dedicated Weather teams sounds really annoying to build against since there are 4 different styles and multiple potential abusers to cover for. If we get rid of Primal Weathers I imagine we'd end up in a metagame dominated by Weather teams, which would likely result in them facing bans as well. Primal Weathers offer a check to these teams that require Weather builds to make some sacrifices in order to succeed - sacrifices that can make them easier to handle as a whole without immediately making them unviable. Just because I added something like Primordial Sea Ferrothorn to my team doesn't mean a prospective Sun team can't add something that threatens or lures Ferrothorn in so it can be removed.